Prosthetic hip joint

ABSTRACT

A prosthetic device and more particularly a hip-joint prosthesis having a fully assembled composite structure of a femoral head, neck and shank to be positioned in and on the femur, a cup for positioning in the acetabulum for relative articulation therein to closely approximate the anatomical function of the natural femur head and acetabulum joint with the femoral head and cup being connected with each other to restrain their separation, but to permit their relative movement.

3 United States Patent [191 Giliberty 1111 3,813,699 I June 4, 1974 1PROSTHETIC HIP JOINT [76] Inventor: Richard P. Giliberty, 824 Hunt Lane,Manhasset, NY. 11030 [22] Filed: Jan. 15, 1973 [21] Appl. No.: 323,828

[52] US. Cl. 3/1, 128/92 C, 128/92 CA [51] Int. Cl. A61f 1/24 [58] Fieldof Search..... 3/1; 128/92 C, 92 CA, 92 R [56] References Cited UNITEDSTATES PATENTS 3.715.763 2/1973 Link 3/1 3,744,061 7/1973 Frost 3/1FOREIGN PATENTS OR APPLICATIONS 1.047.640 7/1953 France 128/92C1,215,737 12/1970 Great Britain 128/92 C Primary Examiner-Richard A.Gaudet Assistant Examiner-Ronald L. Frinks Attorney, Agent, or FirmBauer& Amer 5 7] ABSTRACT A prosthetic device and more particularly ahip-joint prosthesis having a fully assembled composite structure of afemoral head, neck and shank to be positioned in and on the femur, a cupfor positioning in the acetabulum for relative articulation therein toclosely approximate the anatomical function of the natural femur headand acetabulum joint with the femoral head and cup being connected witheach other to restrain their separation, but to permit their relativemovement.

10 Claims, 3 Drawing Figures 1 PROSTHETIC HIP JOINT BACKGROUND OF THEINVENTION Since arthroplasty was first introduced in about 1827, manysurgical procedures have been attempted to produce the idealpseudarthosis. These encompassed attempts to create artificial jointswhich would closely meet the anatomical function of the pre-existingdiseased part and still be relatively painless. Such recent attempts areexemplified by United States Letters Patent to Scales et al U.S. Pat.No. 3,584,318, Haboush U.S. Pat. No. 2,668,531 and U.S. Pat. No.3,067,740.

Prior attempts at the creation of artificial joints have included theprovision of artificial femur heads and acetabulum sockets replacing theoriginals. Unfortunately, erosion and arthritis that sometimes takesplace between the artificial insert and the body causes a ma]relationship that produces new and additional problems. To overcome suchproblems, attempts have been made to cover the acetabulum withprotective cups or shields which have been fastened to the acetabulum bypins, glue or other securing means.

The surgical procedures are complicated, time consuming and oftenperformed at different times and require approximately 2 to 3 hours toperform during which the mortality or morbidity rate is high. Oftentimesthe functioning of the resultantjoint still does not permit a smoothmovement between the head and the secured acetabulum to any great extentespecially after a reasonable period of time.

SUMMARY OF THE INVENTION The present invention is directed to aprosthetic device and more particularly to a hip-joint prosthesisalthough not specifically limited thereto.

An object of the invention is to provide a prosthesis that may besubstituted for and to take the place of the natural anatomic structureand perform the same functions in substantially the same manner as suchreplaced structures were intended to perform.

Another object of the invention is to provide a prosthesis which is acomposite of essentially non-separable parts capable of substantiallyfrictionless articulation. In carrying out the above, an object andfeature of the invention resides in the composite arrangement ofdetailed structures which enable a smooth cup to be inserted intorelative articulating contact with the acetabulum while a femur head isretained within the cup and permitted substantially frictionlessarticulation relative to the cup.

Still a further object is to provide a prosthesis of assembled detailsthat may be installed and substituted for the related anatomy in asingle surgical procedure, in a fraction of the time required for priorsimilar surgical procedures to thereby reduce the mortality an morbidityrate.

It is another object of the present invention to provide an improvedhip-joint prosthesis overcoming the shortcomings of the prior art.Specifically, it is an object to provide an artificial hip-jointprosthetic device in which a cup is utilized for touching andarticulating engagement with the acetabulum, thereby avoiding thepinning, gluing and other securing means that have been utilized andtaught in the prior art. Further, the femur head is permitted relativesubstantially frictionless articulation within the cup while the headand the cup are restrained from relative separation, thereby permittingthe surgical procedure to be accomplished all at one time and enablingalternate articulation between the head and the cup in the event the cupand the acetabulum should for some reason become restricted in theirarticulation.

The above description, as well as further objects, features andadvantages of the present invention, will be more fully appreciated byreference to the following detailed description of a presentlypreferred, but nonetheless illustrative, embodiment in accordance withthe present invention, when taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a partial perspective view illustrating the prosthetic deviceas applied to the hip joint according to the teaching of the presentinvention;

FIG. 2 is an isolated front elevational view, on an enlarged scale, ofthe prosthetic device in its unassembled condition; and

FIG. 3 is a partial front elevational view, similar to FIG. 2,illustrating the prosthetic device in its assembled condition.

Referring to the drawing, the composite prosthetic device there shown isgenerally identified by the numeral l0. Throughout the description,reference will be made to the use of the prosthesis 10 in connectionwith a hip 12 and more particularly to the acetabulum socket 14. Thisdescription should not constitute a limitation upon the scope of theinvention. The reference of the prosthetic device 10 for use inconnection with the hip is merely to enable a simple and easyexplanation of the invention. Obviously, the invention may be applied toother body parts and is equally applicable in veterinary uses.

The prosthetic device 10 comprises a femoral insert adapted to take theplace of the damaged or diseased femur head. The insert is generallyidentified by the numeral l6 and comprises a stem 18 that is adapted tobe forced into the femur after the natural head of the femur has beenremoved. The stem 18 is provided with an enlarged stop or positioningshoulder 20 that merges with a narrowed neck 22 that extends between thestem 18 and a substitute head 24. Because the narrowed neck 22 isintermediate the stem and the head 24, it joins the two parts togetherto form a single structure. The overall femur insert structure 16 may bemade of any well known metallic material that is inert and that iscommonly or conventionally utilized for these purposes. The specificnature or composition of such material forms no part of this invention,although Vitallium has been conventionally employed for such purposes.-

The head 24 is substantially spherical in shape narrowing toward theneck 22, beyond its diametral line 26. The overall femur insert 16 maybe made as a uni tary, nonseparable structure which may be cast,machined or forged if desired, the method of construction beingimmaterial for the purposes of the present invention.

Cooperating with the femur insert 16 is a universally movable acetabuluminsert cup generally identified by the numeral 28. The acetabulum cup 28is formed as a unitary structure and comprises an outer cup member orliner 30 and an inner cup or liner 32. The'elements 30 and 32 are joinedtogether either by lamination, gluing or any other convenient securingmeans to form the unitary overall acetabulum insert cup structure 28.The outer cup or liner 30 is made of a highly polished, inert metal,such as Vitallium. lts outer surface, being highly polished, free ofradial projections and interruptions is essentially and substantiallyspherical in shape to enable the same to be moved substantiallyuniversally within a corresponding opening or socket that may besubsequently provided at the acetabulum socket 14.

The inner liner 32 is bonded or adhered throughout its surface adjacentto and in engagement with the outer liner 30 so that they form a unitarystructure incapable of relative separation or movement. Themeans foraccommodating or enabling such relative securement between the liners 30and 32 forms no part of the present invention.

The inner liner 32 is composed of a material having low frictionalresistance and apparent high lubricating characteristics. Such materialsas silicone, polyethylene and polyfluroethylene are inert, resilientplastics that may be machined, molded and shaped congruent to that ofthe interior surface of the outer cup or liner 30. The interior of theinner cup or liner 32 thus presents a very smooth essentially sphericalsurface 34 of high lubricity and, therefore, low substantiallyfrictionless engagement with the highly polished surface of the femurhead 24 when the femur head 24 is inserted into the acetabulum insertcup structure 28 as seen in H0. 3. Thus, the interface establishedbetween the head 24 and the lubricating liner 32 provides a universaljoint having very low, substantially frictionless characteristics.

Both cup or liner members 30 and 32 extend beyond a diametral line 36defining the substantially and essentially spherical shape of theinterior of the cup structure 28. The extension of the overall cupstructure 28 beyond the diametral line 36 includes both the outer cup 30as at 38 and the inner cup 32 as at 40. The inner cup 32 is narrowed atthe extension 40 such as is shown by the Wall 42 to form a constrictedopening 44 which defines an entranceway into the interior of theacetabulum insert cup structure 28. The bounding outer wall 38 preventsthe inner wall from resiliently expanding but does not inhibit the wall42 from yielding to enable the insertion of the head 24 into and out ofthe cup 32.

In practice, the cup structure 28 is formed independently of the femurinsert 16. However, before use, the femur insert head 24 is positionedwithin the cup structure 28 so that both elements are connected togetheragainst relative separation for use as a unitary or compo siteprosthetic device 10. In this connection although the opening 44 of theacetabulum insert cup structure 28 is narrower in diameter than thewidest diameter extending across the diametral line 26 of the head 24,the nature of the silicone liner wall 42 is such that the same yieldsslightly under pressure, restricted by the wall 38, and thus upon theapplication of lengthwise pressure, the cup and the head 24 may bejoined together by forcing the head 24 through the opening 44 borderedby the wall 42 and then into the confines of the socket defined by thesurface 34. The head is retained within the socket of the inner cupliner 32 because of the constricted size of the opening 44 and theinsert 16 and the cup structure 28 are restrained and normally preventedfrom relative accidental subsequent separation. Obviously, a surgeon mayseparate the two structures 16 and 28 should he find the same necessary,but in normal use the composite of the inserts l6 and 28 form a unitaryprosthetic device 10.

The connection of the two inserts l6 and 28 is illustrated in FIG. 3. Itshould be obvious to those skilled in the art that the connection formedbetween the highly polished, smooth metallic head 24 and that of thesurface 34 of the acetabulum insert cup structure 28 permitssubstantially frictionless universal movement between the femur stem andthe acetabulum if and when the outer surface of the outer cup or liner30 is positioned within the acetabulum socket l4 and restricted orrestrained from movement relative thereto. Such relative movementbetween the head 24 and the surface 34 is enhanced and facilitated in asubstantially frictionless manner because the inner liner 32 is formedof a very smooth, high lubricity material.

In practice, the femur stem 18 is inserted by being pressed into thefemur 46 as seen in FIG. 1 after the natural femur head has beenremoved. The stem is inserted as deep as the shoulder 26 will permit.Thereaf ter, the acetabulum socket 14 is reamed or shaped by the surgeonto conform it substantially congruent to that of the outer highlypolished surface of the outer liner or cup 30, which is then placedwithin such shaped socket. All of this is performed in single opera tionwithout the need to pin, glue, bolt or otherwise secure the cup 30 tothe acetabulum. The operation is quite simple and can be performed in asingle procedure reducing mortality and morbidity to a very low rate.

When the surgical procedure is completed, the acetabulum insert cupstructure 28 is permitted relative universal movement with respect tothe acetabulum socket 14 which has been shaped thereto. It is recognizedthatthe body tends to reject the prostethic device 10 in some instances,in other instances disease and erosion as well as the accumulation ofcartilage and other body accumulations may restrict the continued freemovements of the femur 46 relative to the hip 12 at the interfacebetween the outer surface of the outer cup 30 and the socket 14. In suchinstances, a secondary or alternate movement is permitted at theinterface between the head 24 and the highly lubricated surface 34.Hence, in spite of the fact that the acetabulum insert cup structure 38may subsequently become locked, or restricted and perhaps even totallyimmovable relative to the acetabulum socket 14 at the interfacetherebetween, continued, unrestricted, substantially universal movementof the femur 46 is permitted between the head 24 and the lubricatingliner 32.

The interface movement between the head 24 or femur 46 and the liner 32or hip 12 is of such nature as to last substantially indefinitely. Withthe prosthesis l0 surgically positioned as described, forces of motionof the hip 12 are divided over large surface areas. When the stress isgreater than that able to be absorbed by the interface between the head24 and liner 32, such forces are further distributed by motion affordedby the interface between the outer smooth surface of the cup 30 and theacetabulum socket 14.

What has been provided is a unique prosthetic device that may be appliedin a single surgical procedure, within a relatively short time and whichwill permit its continued use without securing the same to theacetabulum. And even long after the body may erode or produceconstrictions to movement that might normally occur at the interfacebetween the acetabulum 14a and the acetabulum insert cup structure 28,movement is enabled at the interface of the cup 28 with the head 24.

While there have been shown and described and pointed out thefundamental novel features of the invention as applied to a preferredembodiment thereof, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in the artwithout departing from the spirit of the invention. It is the intention,therefore, to be limited only as indicated by the scope of the claimsappended thereto.

What is claimed is: i

l. A hip-joint prosthesis comprising a replacement member having asubstantially spherical head for placement in articulating relation toan acetabulum opening,

an inner cup fabricated of material of low frictional resistance havinga substantially spherical wall bounding a chamber of a correspondingsubstantially spherical shape and size in relation to that of said headand disposed in covering relation thereover so as to permit initialarticulating traverses of comparatively large extent between said headand said inner cup substantially duplicating the movements of the femurhead relative to the acetabulum,

and an outer cup fabricated of a metal alloy which is inert whendisposed in live body tissue, said outer cup being disposed in coveringfixed relation over said inner cup and having an unbroken, continuouslysmooth outer spherical cup surface free of radial projections andinterruptions for allowing substantially universal articulatingtraverses within the acetabulum opening.

2. A hip-joint prosthesis as defined in claim 1 wherein said outer andinner cups have an annular wall section bounding the opening into saidchamber thereof which is adpated to holdingly engage said spherical headagainst withdrawing movement therefrom.

3. A hip-joint prosthesis as defined in claim 2 wherein said fabricationmaterial of said inner cup is a resilient plastic, such that theassembly of said metal outer cup and said inner plastic cup is adaptedto snap in place over said spherical head.

4. A hip-joint prosthesis as defined in claim 3 wherein said inner cupis a polyethylene.

5. In a prosthesis for replacing at least part of a body jointcomprising, in combination, a substantially spherical head member forplacement 6 in articulating relation in a joint opening,

a socket for said head,

said socket having a continuously smooth unbroken outer substantiallyspherical surface, free of radial projections and interruptions forallowing substantially universal articulating traverses within the jointopening,

said socket and head including cooperating means connecting said socketto and about said head for relative movement but to prevent relativeseparation thereof,

and a low friction liner between said head and socket to permit relativemovement between said head and socket and including means to connect thesame to said head to prevent the relative separation thereof.

6. In a prosthesis as defined in claim 5 wherein said liner isfabricated of a material having a low friction surface. I

7. In a prosthesis as defined in claim 6 wherein said cooperating meansconnecting said socket, liner and head comprises interfittingsubstantially spherical shapes permitting the insertion of said linerwithin said socket and said head within said liner.

8. In a prosthesis as defined in claim 7 wherein said fabricationmaterial of said liner is a resilient plastic such that the assembly ofsaid socket and said liner is adapted to snap in place over said head.

9. In a prosthesis as defined in claim 8 wherein said liner ispolyethylene.

10. A hip-joint prosthesis comprising a femur stem, a femurconfigured'head, and a neck narrower than said stem and headintermediate the same to connect said head and stem together,

a cup having an unbroken, continuously smooth outer surface free ofprojections and interruptions for insertion into and for allowingsubstantially universal traverses within an acetabulum opening,

a liner of inert low-friction material retained in said cup againstremoval therefrom,

said liner having a socket defined therein,

said head being movable within and relative to said socket,

said socket having a smooth surface shaped to correspond with that ofsaid head and said socket terminating in narrowed opening engageablewith and about said head adjacent said narrower neck to restrain thewithdrawal of said head from said socket through said opening.

U'NI'IED STATES PATENT OFFICE (lER'lHilC/Yllfl F CORRECTION Patent 3. 813.699 Dated June 4, 1974 IH 'RICHARD P GILIBER'IY It is certified thaterror appears in the above-identified patent and; that said LettersPatent are hereby corrected as shown below:

IN THE CLAIMSr Claim 2, Line 4, change "adpated" to -adapted- Claim 9,Line 2, before "polyethylene" insert -a- Signed and sealed this 1st dayof October 1974.

(SEAL) Attest:

'McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner ofPatents

1. A hip-joint prosthesis comprising a replacement member having asubstantially spherical head for placement in articulating relation toan acetabulum opening, an inner cup fabricated of material of lowfrictional resistance having a substantially spherical wall bounding achamber of a corresponding substantially spherical shape and size inrelation to that of said head and disposed in covering relationthereover so as to permit initial articulating traverses ofcomparatively large extent between said head and said inner cupsubstantially duplicating the movements of the femur head relative tothe acetabulum, and an outer cup fabricated of a metal alloy which isinert when disposed in live body tissue, said outer cup being disposedin covering fixed relation over said inner cup and having an unbroken,contiNuously smooth outer spherical cup surface free of radialprojections and interruptions for allowing substantially universalarticulating traverses within the acetabulum opening.
 2. A hip-jointprosthesis as defined in claim 1 wherein said outer and inner cups havean annular wall section bounding the opening into said chamber thereofwhich is adpated to holdingly engage said spherical head againstwithdrawing movement therefrom.
 3. A hip-joint prosthesis as defined inclaim 2 wherein said fabrication material of said inner cup is aresilient plastic, such that the assembly of said metal outer cup andsaid inner plastic cup is adapted to snap in place over said sphericalhead.
 4. A hip-joint prosthesis as defined in claim 3 wherein said innercup is a polyethylene.
 5. In a prosthesis for replacing at least part ofa body joint comprising, in combination, a substantially spherical headmember for placement in articulating relation in a joint opening, asocket for said head, said socket having a continuously smooth unbrokenouter substantially spherical surface, free of radial projections andinterruptions for allowing substantially universal articulatingtraverses within the joint opening, said socket and head includingcooperating means connecting said socket to and about said head forrelative movement but to prevent relative separation thereof, and a lowfriction liner between said head and socket to permit relative movementbetween said head and socket and including means to connect the same tosaid head to prevent the relative separation thereof.
 6. In a prosthesisas defined in claim 5 wherein said liner is fabricated of a materialhaving a low friction surface.
 7. In a prosthesis as defined in claim 6wherein said cooperating means connecting said socket, liner and headcomprises interfitting substantially spherical shapes permitting theinsertion of said liner within said socket and said head within saidliner.
 8. In a prosthesis as defined in claim 7 wherein said fabricationmaterial of said liner is a resilient plastic such that the assembly ofsaid socket and said liner is adapted to snap in place over said head.9. In a prosthesis as defined in claim 8 wherein said liner ispolyethylene.
 10. A hip-joint prosthesis comprising a femur stem, afemur configured head, and a neck narrower than said stem and headintermediate the same to connect said head and stem together, a cuphaving an unbroken, continuously smooth outer surface free ofprojections and interruptions for insertion into and for allowingsubstantially universal traverses within an acetabulum opening, a linerof inert low-friction material retained in said cup against removaltherefrom, said liner having a socket defined therein, said head beingmovable within and relative to said socket, said socket having a smoothsurface shaped to correspond with that of said head and said socketterminating in narrowed opening engageable with and about said headadjacent said narrower neck to restrain the withdrawal of said head fromsaid socket through said opening.